623
FXUS62 KCHS 141753
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
153 PM EDT Sat Jun 14 2025

.SYNOPSIS...
Atlantic high pressure will build across the Southeast United
States through the weekend into next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Through This Evening: Scattered to numerous showers/tstms
continue to expand in coverage across Southeast South Carolina
and Southeast Georgia this afternoon. Near term guidance is
beginning to hint that convection may concentrate in the
Savannah Metro-Charleston Metro corridor over the next few
hours as inland convection propagates to the east and intersects
the resultant sea breeze circulation. The airmass over this
area remains warm and moist with PWATs well over 2 inches. Given
the moderate to locally strong instability in place, a slight
uptick in coverage through sunset seems reasonable. Pops were
adjusted up to the 60-80% range through early evening, highest
along the lower South Carolina coastal counties. HREF 10km
neighborhood probabilities show modest probabilities of 20-30%
for rainfall amounts >2" in this area with an increased
potential for some convective training. This could yield some
flooding issues, especially in the more urbanized areas of the
Charleston Metro Area (including Downtown Charleston) as well as
other low-lying and poor drainage out in the more rural spots.
Shear remains weak, but a few strong to marginally severe tstms
could occur with strong/damaging winds, locally heavy rainfall
and cloud-to-ground lightning all possible.

Overnight: Convection should quickly wind down after sunset with
dry conditions prevailing overnight. It will remain warm with
lows dropping into the lower-mid 70s inland to around 80 at the
beaches and Downtown Charleston.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
Afternoon showers and thunderstorms are in the forecast for
each successive day in the short term as South Carolina and
Georgia remain on the periphery of a mid-level ridge. Further
west over the ArkLaTex, a mid level weakness will start to break
off from the main flow with mid-level ridging remaining
centered over northwest Mexico and east of Florida. The weakness
will remain close enough to allow for daily afternoon showers
and thunderstorms. Usually when this type of synoptic setup
occurs, convective initiation occurs sooner than pure
climatology (12 - 2 PM instead of a 2 - 4 PM start time). Mean
cloud layer flow on Sunday and Monday is mostly 15 kt or less,
so the probability for any severe weather is forecast to remain
<5%. On Tuesday, mean cloud layer flow does tick up to around 20
kt, but this still will keep severe probabilities below 5%. The
main threat with this type of setup will be for locally heavy
rainfall as mean flow is weak with PWATs around 2.00". Expect
high temperatures to be near 90 degrees F each day with lows in
the mid 70s. Head index values are forecast to reach around 100
degrees F each day.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Not much change in the sensible weather Tuesday night through
Saturday. The pattern continues to support daily chances for
showers and thunderstorms with high temperatures slightly
warmer, or in the low 90s. Heat indices will remain below Heat
Advisory criteria of 108 degrees F, but will still be in the
103-107 degrees F range.

Taking a look at the cluster analysis, also supports the above.
Interestingly, the latest run of the deterministic GFS shows a
mid- level low breaking off over New England by the end of the
long term with a back door front possibly sliding through South
Carolina. However, the cluster analysis shows little in the way
of ensemble support for this with around 9% of the overall
ensemble solution space (GEFS, GEPS, EPS) with some variant of
this answer, while the other ~91% of the ensemble space showing
a much less amplified mid- level low.

&&

.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
14/18z Aviation Discussion:
KCHS/KJZI/KSAV: Showers/tstms are starting to develop and should
primary be an issue for KCHS and KSAV as the sea breeze meanders
past KJZI. Near term guidance favors KCHS for the greatest
impacts, so a TEMPO for MVFR conditions in TSRA was introduced
21-24z, although this may need to be moved up pending last
minute radar trends. VCTS was highlighted for KSAV and KJZI
through 00z for now, but again, last minute radar trends may
change this approach. VFR will prevail overnight for all
terminals.

Extended Aviation Forecast: Brief flight restrictions are
possible in showers and thunderstorms each day, mainly in the
afternoon.

&&

.MARINE...
Tonight: Sea breeze influences will quickly wane this evening
with south to soutwest winds around 15 kt prevailing through
the night. Seas will average 2-4 ft. A few strong tstms could
impact the coastal waters this evening as convection overland
makes a run to the coast. A few Special Marine Warnings for
wind gusts >34 kt may be needed over the coming hours.

Sunday through Thursday: Typical summertime conditions will
prevail over the waters with high pressure centered offshore of
the Southeast United States. A broad, southerly wind regime can
be expected with winds generally averaging 15 kt or less, except
a bit higher along the land/sea interface and Charleston Harbor
each afternoon with the sea breeze. Seas will remain 4 ft or
less through the period.

Rip Currents: Swell will begin to increase in period to around
9s on Sunday with a southwest wind around 10 to 15 kt. This will
continue into Monday allowing a moderate risk of rip currents
to persist at all area beaches through Monday.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$